Just installed a Nest v3 thermostat. Now looking at putting in Nest wired Protect CO & Smoke detectors. Since we are doing a major development, we need to get the sparky doing all the electrics to provide us with Part P certificate. In his view, he is not confident that the regs will allow for a smart Smoke/CO. The question is what happens when the wi-fi/Internet is knocked off during a fire?? He has currently installed standard wired Smoke/COs. Sorry if this has been asked before. Anyone has any experience in this? Also any leads for getting best deals on a couple of Protects highly appreciated.